Anti-allergy drops found to be safe with continuous-wear contacts

Contact Lenses and Eyewear

Issue: October 2006

ByBob Kronemyer

Patanol (olopatadine, Alcon Laboratories) drops used in combination with Focus Night & Day extended-wear contact lenses (CIBA Vision, Duluth, Ga.) were found to be safe, according to a study presented as a poster at Optometry’s Meeting, the annual American Optometric Association Congress.

“Patanol 1% ophthalmic drops, dosed twice daily, are prescribed for relieving signs and symptoms of ocular allergy,” said Brian A. Padgham, OD, and colleagues at Northeastern State University Oklahoma College of Optometry, in Tahlequah, Okla. “Benzalkonium chloride (BAK), a preservative historically known for causing complications with hydrogel lens wear, is the preservative used in Patanol ophthalmic drops.”

The Night & Day silicone hydrogel lens is approved for 1-month extended wear.

The authors noted that extended-wear soft contact lens wearers are often advised by eye care professionals to remove their lenses when instilling topical antihistamines for ocular allergy relief. However, this recommendation is unwelcome news to the patient who desires the intended benefit of these lenses, said Padgham and colleagues in the poster. “The potential complications of dosing topical anti-allergy drugs over silicone hydrogel contact lenses are not fully understood,” the authors said.

The purpose of the study was to assess the ocular signs/symptoms and lens absorption of BAK in patients who dosed their extended wear lenses with Patanol twice daily for 1 month.

Study design

In spring 2005, 19 patients were evaluated for initial visual acuity, contact lens movement/centration, bulbar conjunctival staining, corneal staining, edema and vascularization. Each patient also received a questionnaire on symptoms of lens wear, along with a new pair of Night & Day lenses and three bottles (1 mL) of BAK-preserved Patanol.

Patients instilled Patanol twice a day (12 hours apart) in one randomly chosen eye. The other eye was the control. All patients were reexamined at 1 month post-lens insertion, at which time they also completed a second questionnaire.

BAK absorption was determined by removing the lenses and placing them in individual glass vials with 2 mL of sterile saline. The solution was then analyzed for the presence of BAK, using high performance liquid chromatography (HPLC).

Study results

Fifteen patients completed the 1-month study period, during which no signs of BAK ocular toxicity were detected. However, at the end of the study period, the Patanol lens group “had a strikingly fewer number of mucin balls than the control lens group,” the authors said in the poster.

Comparing the two sets of questionnaires (before and after), only two of the subjective variables showed statistical significance. The overall discomfort score worsened for the control group (P = 0.026), whereas the burning score improved for the control group (P = 0.048).

BAK findings

HPLC analysis of BAK occurred in 33 lenses: 15 pairs of worn lenses (15 Patanol and 15 control) and 3 unworn lenses. “A comparison of the worn Patanol lenses to the worn control lenses showed no apparent differences between the two groups,” the authors said. Similarly, when the worn lenses (Patanol and control) were compared to a standard BAK solution of 0.5 parts per million (ppm), BAK was not detected above 0.5 ppm.

“With no observable ocular toxicity, no subjective changes over time, and no evidence of BAK in the analyzed solutions, we conclude that the concurrent use of Patanol with Night & Day lenses proved safe in this pilot study,” said the authors. However, following HPLC analysis, “we are still unsure whether the BAK was simply not absorbed into the lens matrix or whether the BAK was absorbed into the lens matrix but not readily leached out.”

Likewise, the authors are uncertain as to the cause of decreased mucin balls in the Patanol group. They stated that it was likely caused by either a flushing effect or a decrease in mucin production.

The authors also advocate further studies to fully understand their findings.

For more information:

Corresponding author Latricia Pack, OD, FAAO, is an associate professor at Northeastern State University, Oklahoma College of Optometry. She can be reached at 1001 N. Grand Ave., Tahlequah, OK 74464; (918) 456-5511, ext. 4044; fax: (918) 458-2104; e-mail: packl@nsuok.edu. Dr. Pack has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.

Reference:

Padgham BA, Smith JT, Pack L. The safety of concurrent Patanol instillation over Focus Night & Day extended wear contact lenses. Presented at Optometry’s Meeting, the annual AOA Congress, June 21-25, 2006; Las Vegas.